1. Field of the Invention
Aspects of the present invention relate to a secondary battery.
2. Description of the Related Art
As portable, light-weight, high-end devices, such as video cameras, portable phones, portable computers, and the like, have become more popular, research and development related to secondary batteries, which are used to power these devices, have also been conducted. There are various types of secondary batteries, such as nickel-cadmium (Ni—Cd) batteries, Nickel-Metal hydride (Ni-MH) batteries, Nickel-Zinc (Ni—Zn) batteries, and lithium ion batteries. In particular, lithium ion batteries are widely used in high-tech electronics, because they are rechargeable and can have a small size, a high capacity, a high operating voltage, and a high energy density per unit weight.
A lithium ion secondary battery includes an electrode assembly, a can to house the electrode assembly, and a cap assembly to seal an opening of the can. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator disposed therebetween. During the assembly, two electrode taps of the electrode assembly are welded to a cap plate and a terminal plate of the cap assembly. In the related art, the two electrode taps are resistance welded to the cap assembly. However, resistance welding can interfere with the periodic maintenance of the electrodes (grinding and replacement), due to electrode wear, and can result in defective electrodes, due to spatter generated during the resistance welding.